Topic 2 Hardware Revision

Topic 2 Hardware Revision

1. 2.1 Input and Output Devices

   • Input
     • Examples
       • Microphone
       • Scanner
       • Mouse
       • Touch pad
       • Keyboard
   • Output
     • Examples
       • Speaker
       • Printer
       • Moniter
       • Headphones
       • Projector
   • Both
     • Examples
       • Headset
         • Microphone
         • Speaker/Earphone
       • Phone
         • Speaker
         • Microphone
       • Fax machine
         • Scanner
         • Printer

2. Secondry storage

   • We need it to hold things such as
     • The operating system
     • Any programs and applications that the User installs onto the computer
     • Any files and documents containing the users data
   • Examples
     • Magnetic hard drive
       • Advantages
         • Cheaper than Solid state
         • Comes in 120gb-3tb
       • Disadvantages
         • Moving parts make it easier to break
         • Not portable
         • Can crash
       • Direct access
     • Optical disks
       • Advantages
         • Portable
         • Cheap
         • Most computers can read either a DVD or CD
       • Direct access
       • Disadvatages
         • A small scratch will corrupt data
         • Not much storage
           • CD around 650mb
           • DVD around 9gb
         • Need the correct equipment to read DVD
     • Tape storage
       • Sequential access
       • Advantages
         • Cheap
         • Can store over 100gb
       • Disadvantages
         • Slow access to data
         • Tape is not robust
         • Need special equipment to read and record data on the tape
     • Solid state (Memory stick)
       • Direct access
       • Advantages
         • Hold lots of data. From 1gb up
         • Very portable
         • Reliable due to no moving parts
       • Disadvantages
         • Expensive
         • Can be lost easily
         • The metal part instead into the USB can be damaged easily

3. The CPU

   • The Control Unit
     • Controls and monitors the hardware
     • Controls the input and output of data
     • Fetch-Execute cycle
   • The arithmetic and logic unit (ALU)
     • Arithmetic part
       • Performs calculations on the data
     • Logic part
       • Deals with logic and comparisons. For example it works out if a value is greater then, less than or equal to another
   • The immediate access stores or registers
     • Fast temporary memory in the processor where th ALU or the CU can store and change values
   • Job: Proccess data

4. Logic gates

   • Not
     • Triangular
     • Outputs the opposite to the input
     • 1 input
   • And
     • D shape
     • Tells us if both inputs are 1
     • 2 input
   • Or
     • Rocket shape
     • Tells us if one on the input is 1
     • 2 inputs

5. ROM and RAM

   • RAM
     • Volatile- Anything stored in Ram will be lost as soon as the computer is turned off
     • Used for storing instructions while a program is being executed
     • The more gig or meg, the more operations or programs it can handle at the same time
   • ROM
     • Stores the instructions used to boot the computer up
     • Part of the mother board
     • Read only data

6. Cpu Performance

   • Cores
     • This means it can do more than one program at once
     • Takes time to split instructions up
   • Clock speed
     • How many instructios a computer can fetch-decode-execute per tick of the clock
     • Usually measured in gigahertz (gHz)
   • Processor type
     • Cisc-Desktops
       • Instructions
         • More
         • Better at complex
       • Physical Size
         • Larger and require more silicone to make
       • Speed
         • Faster
         • Higher clock speed
       • Energy consumption
         • More electricity is needed
       • Design
         • Built in
         • Uses a fan
       • Cost
         • More expensive
     • Risc-Smartphones
       • Instructions
         • Less
         • More efficient at simpler tasks
       • Physical size
         • Smaller
       • Speed
         • Slower
         • Lower clock speed
       • Energy consumption
         • Less and can go in sleep mode
       • Cost
         • Cheaper
       • Design
         • Chip